Real corrections to Higgs boson pair production at NNLO in the large top quark mass limit

In this paper we consider the next-to-next-to-leading order total cross section of Higgs boson pair production in the large top quark mass limit and compute four expansion terms in 1/mi. To this end, we analytically compute the real-virtual and double-real contributions to the total cross section and combine them with the existing virtual contribution. Good convergence is observed below the top quark threshold, which makes our results a valuable input for approximation methods which aim for next-to-next-to-leading order corrections over the whole kinematic range. We present details on various steps of our calculation; in particular, we provide results for three- and four-particle phase-space master integrals and describe in detail the evaluation of the collinear counterterms.

Automated summary

In this paper, we study the next-to-next-to-leading order total cross section of Higgs boson pair production in the large top quark mass limit and calculate four expansion terms. We analytically compute the real-virtual and double-real contributions to the total cross section and combine them with the existing virtual contribution. We observe good convergence below the top quark threshold, making our results a valuable input for approximation methods aiming for next-to-next-to-leading order corrections over the entire kinematic range.